In most common use, server is a physical computer (a hardware system) dedicated to running one or more such services (as a host),to serve the needs of users of the other computers on the network. Depending on the computing service that it offers it could be a database server, file server, mail server, print server, web servers, or other.

In the context of client-server architecture, a server is a computer program running to serve the requests of other programs, the "clients". Thus, the "server" performs some computational task on behalf of "clients". The clients either run on the same computer or connect through the network.

Types of servers
In a general network environment the following types of servers may be found.
Application server, a server dedicated to running certain software applications.
Catalog server, a central search point for information across a distributed network.
Communications server, carrier-grade computing platform for communications networks.
Database server, provides database services to other computer programs or computers.
Fax server, provides fax services for clients.
File server, provides file services.
Game server, a server that video game clients connect to in order to play online together.
Home server, a server for the home.
Name server or DNS server.
Print server, provides printer services.
Proxy server, acts as an intermediary for requests from clients seeking resources from other servers.
Sound server, provides multimedia broadcasting, streaming.
Standalone server, an emulator for client–server (web-based) programs.
Web server, a server that HTTP clients connect to in order to send commands and receive responses along with data contents.

A workstation is a high-end microcomputer designed for technical or scientific applications. Intended primarily to be used by one person at a time, they are commonly connected to a local area network and run multi-user operating systems. The term workstation has also been used to refer to a mainframe computer terminal or a PC connected to a network.

Historically, workstations had offered higher performance than desktop computers, especially with respect to CPU and graphics, memory capacity and multitasking capability. They are optimized for the visualization and manipulation of different types of complex data such as 3D mechanical design, engineering simulation (e.g. computational fluid dynamics), animation and rendering of images, and mathematical plots. Consoles consist of a high resolution display, a keyboard and a mouse at a minimum, but also offer multiple displays, graphics tablets, 3D mice (devices for manipulating and navigating 3D objects and scenes), etc. Workstations are the first segment of the computer market to present advanced accessories and collaboration tools.

Presently, the workstation market is highly commoditized and is dominated by large PC vendors, such as Dell and HP, selling Microsoft Windows/Linux running on Intel Xeon/AMD Opteron. Alternative UNIX based platforms are provided by Apple Inc., Sun Microsystems, and SGI.

Workstation class PCs

A significant segment of the desktop market are computers expected to perform as workstations, but using PC operating systems and components. PC component manufacturers will often segment their product line, and market premium components which are functionally similar to the cheaper "consumer" models but feature a higher level of robustness and/or performance. Notable examples of this are the AMD Opteron, Intel Xeon processors, and the ATI FireGL and Nvidia Quadro graphics processors.